1. Field of the Invention
The present invention relates to a fuel cell system and in particular to a fuel cell system using a solid polymer membrane as an electrolyte membrane.
2. Description of the Related Art
In a general fuel cell system, after power general performance is decreased due to impurities in a fuel cell, the polarities of the fuel cell are reversed to draw out a current and to move and discharge impurity ions from an electrolyte membrane (refer to, for example, Japanese patent No. 3475869).